Process for the manufacture of sodium bicarbonate



Sept. 26, 1933. LAWARREE 1,928,540

v PROCESS FOR THE MANUFACTURE OF SODIUM BIC'ARBONATE Filed Feb. 3, 1932 2mm W 1 A E L 3 5 E Co zuauco zumcmq mncz v I VWfri fl nr'z lLwav-re Wile-7 PROCESS FOR THE MANUFACTURE OF I SODIUM BlICARBONATE Henri Lawarre, Brussels, Belgium Application February 3, 1932', Serial No. 590,716,

. and in Germany February 16, 1931 6 Claims. (01. 23-65) The present invention relates to a cyclic procmonium, suchas the chlorides formed from the ass for the manufacture of sodium bicarbonate original sodium salt, and from the sodium salt starting with a sodum salt such as sodium chlosubmitted to bicarbonation. The role of the salts ride. v i Q g i of the substituted trimethylamines is to render The use of trimethylamine for the manufacture complete reactions which are only partial with of alkaline carbonates has itself I alreadyflbeen ammonium salts alone. proposed particularly in theprocesses forming Other details of the invention will appear in the object of German Patents Nos- 5,786,, 9,376 the course of the description of the two examples and 13,397. below and of the appended diagram, which repre 10 However, apractical process based on this :consentby way of example only," a method of realizacept has not as yet been devised because in ac.- tion of the invention. cordance with the known processes it is necessary totreat the residue obtained after the precipita Example 1 tion of the sodium bicarbonate. p v I 15 This treatment has up until the present ren- In the vessel I there is introduced a solution dered the use of trimethylamine for the manucontaining 94 of ium chloride, 190 kg. f facture of sodium bicarbonate practically imtrimethylamine chlo and 98 kg. of ampossible, v V ,monium chloride per cubic meter (correspond- According to the l r snt vention, 1 utiliz ing to saturation in the case of this latter salt).

2o asolution circulating in a cycle and which con- The 94 kg. of NaCl does not take an active part tains jointlythe soluble salts of niethylamine and in the reactions and is once for all introduced ammonia. I A v W at the start of the'cyclic operation after which AS Salts of 'inethylamines; I: provide for the it circulates in a cycle with the vehicular solution. use of salts of mono, di or trimethylamines or There is added to the solution 140 kg. of fresh 25 mixtures of these salts. z I p sodium chloride and 156 kg. of neutral carbonate I add to the solution, the soluble sodium salt to of ammonium (NI-102003 inthe form of NI-Iz,

be transformed intobicarbonate, in the presence CO2 and washing Wate i om p ous operaof CO2 and ammonia or ammonium carbonates n. There is precipitated about 125130. which will effect the precipitation of a quantity of ammonium chloride, pra ic y p Q 1- 30 f ammonium' salt practically correspondin to responding substantially to the 140 kg. of sodium the total amount of sodium salt introduced; after chloride freshly introduced. c which I eliminate this precipitate and introduce After filtration of this ammonium chloride, the into the filtrate, 002 or ammonia and CO2 for presolution contains trim hyl mine carbonates, am-

cipitating sodium bicarbonate with regeneration monium carbonates and sodium chloride. This 1 35 of the separated solution of salts of methylamines solution is still saturated with the above-men and ammonia. tioned 198 kg. of ammonium chloride.

According to a particular method of carrying The carbonation of this solution in the Vessel out the invention, there is employed in a cycle a 11 causes the precipitation of about 200 kg, of

solution of a salt of methylamine and a sodium sodium bicarbonate corresponding to almost the F salt, which is kept saturated with NH4C1. In whole of the 140 kg. of sodium chloride freshly 9 this manner the ammonium chloride formed by introduced at the beginning of the operation. I the double decomposition above mentioned is The above-mentioned 94 kg. of NaCl do not precipitated and is eliminated by filtration. take any active part in the reaction and are once By transforming the carbonates of trimethyland for all introduced at the first cycle operation, amines into bicarbonates by means of gaseous after which the whole of the sodium chloride C02 or ammonium carbonates, respectively, C02 employed, that is to say, kg. percycle and per and ammonia gas, there is obtained the precipicubic meter are transformed into bicarbonate, tation of sodium bicarbonate by the joint action while the 94 kg. remain in the circulating solution. of the bicarbonate of the methylamine, and or The precipitation of sodium bicarbonate entails salt of sodium such as the chloride. After filtra- This can be advantageously compensated for by tion of the bicarbonate of sodium precipitated, an addition of wash water comingfrom a prethere is re-in'troducedinto the cycle without any ceding operation. treatment, the residual solution, which is satu- After filtration of the sodium bicarbonate pre- T rated with salts of trimethylamines and of am-- cipitated, there is found again in solution the 94 i l bicarbonate of ammonia'inpresence of a single an impoverishment of the solution in water..-,105-

kg. of NaCl 190 kg. of trimethylamine chloride and 198 kg. of ammonium chloride started with.

Example 2 There is introduced into a vessel I a solution containing per cubic meter, 600 kg. of mono di and trimethyl-ammonium nitrates, 190 kg. of NH4C1 or its equivalent 500 kg. of double nitrate of amine and ammonium.

There is added to this solution 210 sodium chloride and neutral ammonium carbonate in the form of NH3 and CO2, and 190 kg..of ammonium chloride, corresponding to the210 kg. of sodium chloride introduced. areprecipitated. All the sodium introduced is made soluble in the form of nitrate. This solution is carbonated in the vessel II by injection of CO2 and there is obtained 300 kg. of bicarbonate of sodium. As

before the loss of water is compensated by means of washing water. The solid ammonium chloride precipitated in the vessel I can be treated with lime in a vessel III and the ammonia obtained can be re-introduced into the cycle in the vessel I at the same time as the regenerated solution obtained after filtration of the bicarbonate of sodium in the vessel II.- This regenerated solution containsthe salts of amines and ammonia started with. i

The final treatment with CO2 in the vessel II of a solution containing besides salts of amines and ammonia, sodium in the form of a single salt (chloride or nitrate), procures a greater yield of sodium bicarbonate than by' any known process, and the yield of sodium salt is of the order of 96 to 98% relative to the quantity of sodium salt employed.

Moreover, by the process described it is possible to efiect methodical washings without loss of products and without necessitating at {any moment either concentration or cooling or other thermal operation. Finally the ammonium chloride obtained is practically free fromsodium chloride. i

What I claim is:

1. A process for the manufacture of sodium bicarbonate comprising adding a soluble sodium salt and ammonium carbonates to a solution of a methylamine salt, carbonating the resulting solution of carbonates of ammonia and amine, and separating the precipitate of sodium bicarbonate formed.

2. A process for the manufacture of sodium .bicarbonatecomprising adding a soluble sodium kg. of

salt and ammonium carbonates to a solution of methylamine salt kept saturated in the ammonium salt corresponding to said sodium salt, separating the precipitate of ammonium salt formed, carbonating the filtered solution of carbonates of ammonia and methylamine, and separating the precipitate of sodium bicarbonate formed.

3. A process for the manufacture of sodium bicarbonate comprising adding a soluble sodium salt and ammonium carbonates to a solution of 'amethylamine salt kept saturated in the ammonium salt corresponding to said sodium salt, separating the precipitate of ammonium salt formed, carbonating the filtered solution of carbonates of ammonia and methylamine, separating the precipitate of sodium bicarbonate formed, and reintroducing in the process the remaining solution.

4. A process for the manufacture of sodium bicarbonate comprising adding a soluble sodium salt and'ammonium carbonates to a solution of methylamine salt kept saturated in the ammonium salt corresponding to said sodium salt,

separating the precipitate of ammonium salt formed, carbonating the filtered solution of carbonates of ammonia and methylamine, separating the precipitate of sodium bicarbonate formed, treating with lime the ammonium salt precipitated, and reintroducing the ammonia liberated the process with the remaining solution.

bicarbonate comprising adding sodium chloride and ammonium carbonates to a solution containing methylamine nitrate saturated with ammonium chloride, separating the precipitate of ammonium chloride formed, carbonating the filtered solution containing carbonates of ammonia and methylamine and sodium nitrate, separating the .precipitate of sodium bicarbonate formed, and

reintroducing in the process the remaining solution.

HENRI LAWARREE. 

